On the other hand, the person is obliged to present a ticket for inspection. It sounds as if the way it was handled and the outcome was a total shambles - but the ticket must still be available for inspection and some responsibility has to lie with the passenger to ensure that can happen and the railway should be accommodating in that.A company cannot dismiss someone instantly for gross misconduct without suspension and investigation, and a hearing, or deny them the right to lodge a grievance or appeal.
Yes, agreed. This can be done by completing the form here: https://www.networkrail.co.uk/wp-content/uploads/2021/09/NR-Subject-Access-Request-Form.pdf
I suspect the guard is not allowed to simply rifle through a person's wheelchair without invitation. Others may be able to offer advice more specific than this, but a wheelchair is in effect an extension of a disabled person and this is akin to dipping your hand into someone's pocket.
We have some regular passengers in similar circumstances and they invariably tell you to get their ticket out of a specific location and ask you to put it back for them, job done. Not inspecting the ticket during a revenue check isn't really the answer.